The in vitro antioxidant activity of trilinolein and other lipid-related natural substances as measured by enhanced chemiluminescence

There ia abundant evidence for the premise that oxygen-derived free radicals (OFR) mediate ischemia/reperfusion injury to the myocardium. OFR scavengers such as superoxide dismutase can effectively reduce damage through lipid peroxidation during ischemia/reperfusion. Enhanced chemiluminescence, which has been used to measure OFR, was used to measure the antioxidant activity of fatty acids (palmitic and linoleic acid) and triglycerides ( triolein, tristearin) and natural plant antioxidants (magnolol, catechin, trilinolein). Trilinolein, which has recently been isolated from natural products, as well as the well-known water soluble analogue of vitamin E - Trolox, were used as control. During pretreatment with chemicals, at concentrations of 10(-9) to 10(-7) M, enhanced chemiluminescence of linoleic acid (C 18:2) showed a dose-responsive reduction of OFR with a maximal mean reduction of -31.9 % when compared to baseline. A saturated fatty acid such as palmitic acid (C 16:0) showed only relatively weak antioxidant activity at concentrations of 10(-7) to 10(-6) M with a maximum reduction of OFR of 15.2 % only. Control chemicals such as trilinolein and Trolox showed significant antioxidant activity. At concentrations between 10(-10) and 10(-6) M and trilinolein has the most potent antioxidant activity with a maximal mean reduction of OFR of 48.0%, whereas Trolox showed only -39.2 %. As for the natural plant antioxidants, only catechin showed potent antioxidant activity (-40 %). Polyunsaturated triglycerides such as triolein (oleic acid, C 18:1) also possess significant OFR scavenging effect (- 31.9 %) whilst saturated triglycerides such as tristearin (stearic acid, C 18:0) had only relatively weak antioxidant activity (- 15.2 %). Generally, the antioxidant activity of unsaturated compounds is stronger than saturated compounds; double-bond existence may partially explain this phenomenon.